I used to build Hawken rifles, what I did to fit them if they were a little off was use a chisel with the sides milled flat if I needed a bit extra space and use a pin punch on the loop if it needed to be tighter.I made a set of these of slightly different thickness as different guns grouped better with different pressure on the wedge.
While I have no doubt that bending the wedge would work I would not recommend it as any slight movement of the key from barrel whip or recoil is liable to change the POI.